Wave and Particle Analysis of Z‐Mode and O‐Mode Emission in the Jovian Inner Magnetosphere
Wave and Particle Analysis of Z‐Mode and O‐Mode Emission in the Jovian Inner Magnetosphere
复制标题
DOI：
10.1029/2022ja031199
复制
发表时间：
2023-04
期刊：
影响因子：
--
通讯作者：
J. Menietti;P. Yoon;T. Averkamp;W. Kurth;J. Faden;F. Allegrini;P. Kollmann;S. Bolton
中科院分区：
文献类型：
--
作者：
J. Menietti;P. Yoon;T. Averkamp;W. Kurth;J. Faden;F. Allegrini;P. Kollmann;S. Bolton
我们报告了朱诺号航天器在木卫一环面内边缘附近的低至中纬度地区绕木星运行时获得的一些最强烈的 Z 模式和 O 模式观测结果。我们已经能够根据观察到的 Z 模式发射的较低频率截止来估计该区域的等离子体密度。如果我们考虑到未测量的冷等离子体，则结果与朱诺号航天器上的木星极光分布实验（JADE）的电子密度测量结果一致。测向测量表明 Z 模式和 O 模式发射具有不同的源区域。我们还使用 JADE 和木星高能粒子探测器仪器测量的相空间密度来计算观测到的 O 模式和 Z 模式发射的估计局部增长率，假设损失锥不稳定性和拟线性分析。结果表明，在源区域附近而非内部观察到了排放，并且自由能源与损失锥体一致。因此，我们对假设的远程 Z 模式和 O 模式波增长进行了拟线性波分析。结果表明，远程产生的波通过不均匀介质传播到卫星位置，可以解释观测到的波特征。 Z 模式在木星内部磁层加速电子方面的重要性使得木星上的这些新的波模式确认特别令人感兴趣。
We report some of the most intense Z‐mode and O‐mode observations obtained by the Juno spacecraft while in orbit about Jupiter in a low to mid‐latitude region near the inner edge of the Io torus. We have been able to estimate the density of the plasma in this region based on the lower frequency cutoff of the observed Z‐mode emission. The results are compatible with the electron density measurements of the Jovian Auroral Distributions Experiment (JADE), on board the Juno spacecraft, if we account for unmeasured cold plasma. Direction‐finding measurements indicate that the Z‐ and O‐mode emission have distinct source regions. We have also used the measured phase space density of the JADE and the Jupiter energetic particle detector instruments to calculate estimated local growth rates of the observed O‐mode and Z‐mode emission assuming a loss cone instability and quasilinear analysis. The results suggest the emissions were observed near, but not within, a source region, and the free energy source is consistent with a loss cone. We have thus carried out the quasilinear wave analysis of the assumed remote Z‐ and O‐mode wave growths. It is shown that the remotely generated waves, propagated through an inhomogeneous medium to the satellite location, may account for the observed wave characteristics. The importance of Z‐mode in accelerating electrons in the inner Jovian magnetosphere makes these new wave mode confirmations at Jupiter of particular interest.